The Minkowski metric, also called the Minkowski tensor or pseudo-Riemannian metric, is a tensor η_αβ whose elements are defined by the matrix (η)_αβ congruent [-1 | 0 | 0 | 0 0 | 1 | 0 | 0 0 | 0 | 1 | 0 0 | 0 | 0 | 1], where the convention c = 1 is used, and the indices α, β run over 0, 1, 2, and 3, with x^0 = t the time coordinate and (x^1, x^2, x^3) the space coordinates.